Preoperative risk stratification in infective endocarditis. Does the EuroSCORE model work? Preliminary results

Abstract

There is an important role for risk prediction in cardiac surgery. Prediction models are useful in decision making and quality assurance. Patients with infective endocarditis (IE) have a particularly high risk of mortality. The aim was to assess the performance of European System for Cardiac Operative Risk Evaluation (EuroSCORE) in IE. The additive and logistic EuroSCORE models were applied to all patients undergoing surgery for IE (Duke criteria) between January 1995 and April 2006 within our prospective institutional database. Observed and predicted mortalities were compared. Model calibration was assessed with the Hosmer-Lemeshow test. Model discrimination was tested by determining the area under the receiver operating characteristic (ROC) curve. One hundred and eighty-one consecutive patients undergoing 191 operations were analyzed. Observed mortality was 28.8%. For the entire cohort the mean additive score was 10.4 (additive predicted mortality of 14.2%). The mean logistic predicted mortality was 27.1%. Discriminative power was good for the additive and the logistic models for the entire series. Area under ROC curve were 0.83 (additive) and 0.84 (logistic) for the entire cohort, 0.81 and 0.81 for the aortic position, 0.91 and 0.92 for the mitral position, 0.81 and 0.81 for the native valve, 0.82 and 0.83 for the prosthetic valves, and 0.81 and 0.51 for the gram-positive microorganisms, respectively. This initial sample may be small; however, additive and logistic EuroSCORE adequately stratify risk in IE. Logistic EuroSCORE has been calibrated in IE, a special group of very high-risk patients. Further studies with larger sample sizes are required to confirm these initial results.